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Saverio Russo: The new silicon

posted 30 Apr 2019, 08:15 by Peter Boggild   [ updated 30 Apr 2019, 08:15 ]
Quantum Systems and Nanomaterials group, Physics Department, University of Exeter, UK. 

The coexistence of semiconducting properties and a stable oxide dielectric suitable for transistor applications are some of the key aspects beyond the success of Silicon. The leap to future imperceptible, wearable and flexible applications is now held back by the lack of mechanical flexibility inherent to a Silicon wafer. The development of sensing and computing on textile fibres(1) and biological tissues poses stringent constrains on the mechanical properties of materials in addition to their optical and electrical characteristics. The discovery of 2D semiconductors characterized by an unprecedented combination of physical properties is enabling a wide range of fundamental and applied science discoveries. However, the lack of a 2D system with a mechanically flexible oxide suitable for transistor, memory, light emitting and sensing devices has been holding back the true potential of these novel systems. In this talk I will present the discovery of a mechanically flexible and air stable high-k oxide obtained from the photo-oxidation of the atomically thin semiconductor HfS2. Hence I will show how spatially controlled photo-oxidation can be used to engineer specific strain patterns in a two-dimensional semiconducting sheet, leading to an unprecedented tailoring of the energy bandgap. I will discuss, how these strain fields can be used to generate built-in electric fields necessary to observe inverse charge-funnelling(2) that is the funnelling of photo-excited charges away from the excitation area towards regions where they can be efficiently separated and collected. Finally I will review the use of this novel mechanically flexible oxide in layered transistors, memories, light emitting devices and photodetectors(3)

[1] E. Torres et al., Nature Flexible Electronics 2, 25 (2018)

[2] De Sanctis A. et al., Nature Communications 9, 1652 (2018)

[3] Peimyoo, N. et al., Science Advances 5, eaau0906 (2019)

Saverio Russo is Associate Professor and academic leader of the Quantum Systems and Nanomaterials group in the Physics Department at the University of Exeter in the United Kingdom. Following a master in Physics at the University of Pisa (Italy) and a master in Materials Engineering from the Katholieke Universiteit Leuven (Belgium), he received the PhD degree in Physics from the Kavli Institute of Nanoscience Delft in the Netherlands in 2007 for pioneering studies on electron transport in hybrid structures. He has joined the University of Exeter in 2010, after securing a JSPS fellowship at the University of Tokyo (Japan). His research focusses on fundamental and applied science of emerging quantum systems to include 2D materials, and his scientific discoveries have regularly been featured by broad audience media to include BBC, NBC, The Guardian, etc.